Ryder T B, Hedrick S A, Bell J N, Liang X W, Clouse S D, Lamb C J
Plant Biology Laboratory, Salk Institute for Biological Studies, San Diego, CA 92138.
Mol Gen Genet. 1987 Dec;210(2):219-33. doi: 10.1007/BF00325687.
Chalcone synthase (CHS) catalyzes the first and key regulatory step in the branch pathway of phenylpropanoid biosynthesis specific for synthesis of ubiquitous flavonoid pigments and UV protectants. In bean (Phaseolus vulgaris L.) and other members of the Leguminoseae, chalcone synthase is also involved in the synthesis of the isoflavonoid-derived phytoalexin antibiotics characteristic of this family. We have demonstrated that the haploid genome of bean contains a family of about six to eight CHS genes, some of which are tightly clustered. Treatment of bean cells with fungal elicitor activates several of these genes leading to the accumulation of at least five and probably as many as nine distinct CHS transcripts encoding a set of CHS isopolypeptides of Mr 42-43 kDa but with differing pI in the range pH 6-7. In elicited cells specific transcripts and encoded polypeptides are differentially induced with respect to both the extent and kinetics of accumulation. Wounding or infection of hypocotyl tissue also activates several CHS genes with marked differences in the pattern of accumulation of specific transcripts and encoded polypeptides in wounded compared to infected tissue or elicited cells, indicating operation of more than one cue for defense gene activation. Illumination induces accumulation of a different set of CHS transcripts including only one of the set hitherto demonstrated to be induced by biological stress. The organization and differential regulation of the CHS gene family in bean are discussed in relation to the functions of this enzyme in adaptative and protective responses to diverse environmental stresses.
查尔酮合酶（CHS）催化苯丙烷类生物合成分支途径中的第一步和关键调控步骤，该途径专门用于合成普遍存在的类黄酮色素和紫外线防护剂。在菜豆（Phaseolus vulgaris L.）和豆科的其他成员中，查尔酮合酶还参与该科特有的异黄酮衍生的植物抗毒素抗生素的合成。我们已经证明，菜豆的单倍体基因组包含一个约有六到八个CHS基因的家族，其中一些基因紧密聚集。用真菌激发子处理菜豆细胞会激活其中几个基因，导致至少五种、可能多达九种不同的CHS转录本积累，这些转录本编码一组分子量为42 - 43 kDa但在pH 6 - 7范围内具有不同pI的CHS同工多肽。在受激发的细胞中，特定的转录本和编码的多肽在积累程度和动力学方面都受到差异诱导。下胚轴组织的创伤或感染也会激活几个CHS基因，与受感染组织或受激发细胞相比，创伤组织中特定转录本和编码多肽的积累模式存在明显差异，这表明防御基因激活存在不止一种信号。光照会诱导另一组不同的CHS转录本积累，其中只包括迄今已证明受生物胁迫诱导的一组转录本中的一种。本文结合该酶在对多种环境胁迫的适应性和保护性反应中的功能，讨论了菜豆中CHS基因家族的组织和差异调控。
